Whale tubercles improve wind turbines
Challenge: more efficient wind turbines
Natural solution: humpback whale Megaptera
Wind is a plentiful renewable resource.
Carefully-sited wind turbines are an environmentally and
economically sustainable way of producing energy. The UK,
with the largest wind energy resource in Europe,
1 could potentially generate a fifth of its
electricity needs from wind power. 2 Globally,
wind could meet a significant proportion of humanity’s energy
needs, and the amount of energy generated by wind power is growing
rapidly each year. However, wind still only provided about
0.5% of total global energy production in 2004.3
One of the main limitations to wind power is its
unpredictable nature. Everyone is familiar with the
way the wind constantly changes speed and direction.
Engineers aim to make wind turbines that are both reliable and
efficient in the prevailing wind conditions. However, there
is a trade off: designs that can get the most energy out of
high-speed winds perform very poorly at low wind speeds, and few
designs can cope well with turbulent air. 4
The main problem is the phenomenon known as stalling.
Aeroplanes can stall when the flow of air over the wings is
disrupted, causing a dramatic loss of lift which can cause the
plane to plunge to earth. Exactly the same thing occurs in
wind turbine blades, but here stalling causes loss of power and can
in extreme cases tear the turbine apart. To work efficiently
at low wind speeds, turbine blades need to meet the wind at a steep
angle – a large ‘angle of attack’ – but this makes stalling more
Historically, wind turbine engineers have been forced to
compromise, with the result that wind energy is not dependable
enough to meet demand and has to have a fossil-fuel back up.
For every 200 megawatts of wind power, at least 100
megawatts of coal power are needed to fill in the gaps when wind
power is not sufficient. 4
The accepted wisdom is that the leading edge of objects
like wings, fins and turbine blades should be smooth and
streamlined, and up until recently wind turbine designs
have been based on this principle. 4
However, in the 1990s a biomechanics expert became interested in
humpback whales. These whales are extremely
agile swimmers, using their mobile flippers to bank and turn to
catch their prey; 6 and yet the flippers are
clearly not smooth, being covered along the leading edge with bumps
called tubercles. A flipper was taken from a dead whale for
detailed study. It was found to be shaped very much like an
aeroplane wing in cross-section, apart from the tubercles.
7 More studies followed, where models of flippers
with and without tubercles were built and tested in wind tunnels.
6, 8 These revealed that the tubercles gave the
flipper more lift and less drag, while allowing the angle of attack
to be increased by 40% before stalling occurred. Finally, in
2008, mathematicians managed to refine their fluid dynamics models
to explain this phenomenon. 9 Decades of
mathematical modelling had been overturned by simply observing how
nature solves the problem. Engineers could now start to
develop more efficient wind turbine designs by adding a bumpy
leading edge to the blades.
This innovation has already been put to commercial
use: a major Canadian company is producing industrial fans
using the tubercle principle, which it claims are 20% more
efficient than conventional fans. However, the inventors of
‘Tubercle Technology’ see wind turbines as the main technology
which will benefit from their discovery. Modelling has shown
that adding bumps to the leading edge of turbine blades directly
addresses the stalling problems described above. The product
is currently being field tested, and the company is already
receiving enquiries from wind turbine manufacturers.
Humpback whales belong to the cetaceans, a group of over
80 species of mammals including whales, dolphins and
porpoises. Within this group, they are one of
the 13 species of baleen whale. 10 Although
humpbacks, like other whales, have historically been killed in
large numbers for their oil, they are now legally protected and
populations are recovering in many places. However, they are
still threatened by habitat loss, chemical and noise pollution,
entanglement in fishing nets, decline of the species they feed on,
and illegal hunting. Some isolated populations may
still be at risk of extinction. 11
Humpback whales are undeniably a charismatic species.
Thanks to their specialised flippers, they are the most acrobatic
of the whales, renowned for their energetic displays. The
flippers, at up to 5m long, are the largest appendage of any
animal on earth. Humpback whale tails (‘flukes’) are as
unique as human fingerprints, and the way they raise them when
diving enables whale-watchers to identify and track individual
whales. Male humpbacks sing the longest, most complex songs
in the animal kingdom. 11 Hundreds of travellers,
whale-watchers and scientists have marvelled at them and fought for
their conservation over the years. However, who could have
predicted that they might one day help to solve the energy crisis
by inspiring a better wind turbine?
Back to Natural Solutions front
- Tucker, G., Bassi, S., Anderson, J., Chiavari, J., Casper, K.
and Fergusson, M. (2008): Provision of
Evidence of the Conservation Impacts of Energy Production.
Institute for European Environmental Policy (IEEP), London, 
pp. & Annexes. Accessed March 2010.
- UK Government’s Department for Energy and Climate Change (2009)
The UK Renewable Energy Strategy. Accessed March
- IPCC: Sims, R.E.H. et al. (2007) Energy Supply.
In Climate Change 2007: Mitigation. Contribution of
working group III to the Fourth Assessment Report of IPCC.
Cambridge University Press, Cambridge.
- WhalePower Accessed
whales inspire new wind turbine technology. Tribology
and Lubrication Technology, 2008. Ed. Dr Neil
Canter. Accessed March 2010.
- D. S. Miklosovic et al. (2004) Leading-edge tubercles
delay stall on humpback whale (Megaptera novaeangliae)
flippers. Physics of Fluids 16
Full article available online. Accessed March 2010.
- Fish F.E. et al. (1995) Hydrodynamic design of the
humpback whale flipper. Journal of Morphology 225:
- Derrick Custodio et al. (2006) Separation Control on a
Hydrofoil Using Leading Edge Protuberances. Bulletin of
the American Physical Society, 59th Annual Meeting of the APS
Division of Fluid Dynamics.
- van Nierop, E. A. et al. (2008) How Bumps on Whale
Flippers Delay Stall: An Aerodynamic Model. Physical Review
Letters 100, 054502
Threatened species of whales and dolphins. World Wide
Fund for Nature (WWF). Accessed March 2010.
Whale and Dolphin Conservation Society (WDCS). Accessed
energy, JNCC. Accessed March 2010.
And Dolphins Influence New Wind Turbine Design. Science
Daily, July 2008. Accessed March 2010.
Dolphins Inspire Wind Turbine Tech. Discovery News, July
2008. Accessed March 2010.